This invention generally relates to partition assemblies, and particularly those made of paperboard material or the like having longitudinal and cross strips interlocked to provide a partition assembly having cells into which containers such as bottles, cans, or the like are inserted. More specifically, this invention relates to such a partition assembly where the longitudinal and cross strips are held engaged by interlocking slots, and further where a glued tab is utilized at each interlock of a cross strip with a longitudinal strip to securely lock the strips together.
Partition assemblies having interlocking longitudinal and cross strips are well known in the art. Examples are shown and described by U.S. Pat. Nos. 4,000,845; 3,948,435; 3,942,837, and 3,942,709. It is also known in the art to use glued flaps, tongues or tabs in a partition assembly.
George U.S. Pat. No. 2,549,801 discloses a partition assembly where the partition strips are zig-zag folded and joined to adjacent zig-zag folded strips by means of glued tongues. However, the tongues are not part of an interlock for joining cross strips.
Gepfer U.S. Pat. No. 3,942,709, owned by the same assignee as the present invention, discloses an interlocking partition with glued end flaps to stabilize the partition, but does not disclose the use of glued tabs at the interlocks.
Martin U.S. Pat. No. 4,226,357 discloses a partition having glued tabs, but the partition is formed from a single blank. The tabs are not part of an interlock for interlocking cross strips.
Other examples of partition assemblies are shown by U.S. Pat. Nos. 1,137,732, 3,446,412, 3,640,445, and 4,219,146.
The present invention specifically relates to partition assemblies having interlocking longitudinal and cross strips, and in accordance with the invention the interlocks have glued tabs to securely interlock the strips. The interlock includes a first slot in a longitudinal strip and a second slot in a cross strip, one of these slots having a tab. A side surface of the tab is adhered to a side wall of the strip having the other slot. The tab is foldable generally along the line of intersection of the longitudinal and cross strip to accommodate unfolding of the partition assembly between collapsed and expanded positions.
To assemble the partition, the longitudinal and cross strips are each formed with their respective slots. In a preferred embodiment of the invention, the cross strips have the slots with tabs. The longitudinal strips that form each partition are fed along a conveyor on their side edges such that the strips are parallel and vertically oriented. The cross strips are formed from a continuous web. The slots having the tabs are die cut for each cross strip as the web moves past the die station. Preferably, then adhesive is applied to one side of the tabs, and the strip is severed from the web. With the longitudinal strips forming each partition in transverse alignment and with their slots opening to their upper edges, the severed cross strip is fed downwardly orthogonally to the longitudinal strips such that its slots engage with aligned slots of the parallel longitudinal strips to interlock the cross strip with each longitudinal strip. This is a continuous process such that the cross strips are fed downwardly in succession to form each partition assembly after the longitudinal strips for a partition assembly are positioned as previously explained.
After each partition assembly is formed, it is collapsed from its fully expanded configuration to a collapsed configuration in a direction such that the glued sides of the tabs engage the side wall of the longitudinal strip or strips to become adhered thereto. The collapsing operation may be done by hand, or with automated equipment such as that disclosed in pending U.S. patent application Ser. No. 06/210,541, filed Nov. 28, 1980, and owned by the same assignee as the present invention. The collapsed partition assemblies are collected into bundles for shipment to the customer.
When each partition assembly is unfolded or expanded for use by the customer, the cross strips again become orthogonal to the longitudinal strips, but the tabs remain glued to the longitudinal strips such that the tabs becomes folded generally along the line of intersection of the strips. To facilitate this folding of the tab, the base of the tab may include perforations, slots or other suitable means.
By means of the glued tab interlock, the present invention provides a partition assembly with interlocking longitudinal and cross strips where the engagement between the strips is very secure and prevents inadvertent separation of the strips during handling and the automated operations to which the assemblies are subjected, and yet provides a partition which is easy to assemble.